Video: Diana Nyad continues swim from Havana to Key West

>>this half hour with the question, will the fourth time be the charm for swimmer
diana nyad
.
mark potter
in miami following her progress. mark, good morning.

>> reporter: good morning to you, lester.
diana nyad
has been swimming out there in the ocean for more than a day and a half now. she ran into a storm last night but still heading to
key west
, hoping to make it all the way this time.

>>after her first full day on the water,
diana nyad
still and to be in good spirits and
going strong
on the 103 mile swim from havana to
key west
. this is
nyad
's fourth attempt to swim across the
florida strait
, something no one has done before. she first tried in
1978
but
bad weather
pushed her off course. just last summer she made two more attempts after one of them was cut short by asthma, she sat down with our own
natalie morales
.

>>you know, it was
such a shame
, natalie. i was so worried. i wasn't even sore. after 30 hours of swimming, no soreness.

>>now the 63-year-old is trying again followed by a team providing nutrition and support, using a kayak with a device that emits an
electric field
hopefully to keep sharks at bay. the biggest problem so far have been jellyfish which rise to the surface at night. members of her crew say she has been stung repeatedly on her neck, lips, forehead. only the
rising sun
brings relief. on her behalf one crew member tweeted, today is more like swimming. i don't know what you would call last night, probably surviving. it is estimated it will take 60 hours for
nyad
to complete the swim, which she is determined to finish.

>>i am not going to quit until i stand on the shore in florida. i'm going to make it across.

>> reporter: now, if she overcomes all the obstacles, stays on schedule, stays on course, she'll arrive in
key west
tomorrow to make history. lester.

>>mark potter
, thanks. mark sullen ger is dine
nyad
's operations chief. he's with us on a phone in a boat right next to
diana
. good morning, thanks for coming on.

>>good morning. thanks for having us.

>>we saw the tweet referring to all hell broke lose. she was off course. how do things look at this hour.

>>actually things couldn't look better right now. the sun is up.
diana
is in, what we call the streamer, which is what she follows. her stroke looks good. we're moving in the right direction.

>>do you have your eyes on her right now?

>>i'm looking at her as we speak.

>>when you look at her, can you tell how she's doing just by her stroke? do you see her face? does she give you indications of how she's feeling?

>>actually we can. we time
diana
's stroke count. that's how many times she strokes per minute. and a good stroke count for her is 50. she's on that number right now.

>>so when you look at her health and the weather conditions, what's your anticipation of when she will -- whether she'll complete this swim and whether she might hit land.

>>that's a good question. unfortunately it's one that's difficult to answer accurately. there are so many variables involved in this with
mother nature
, as you know, that it's really tough for us to give you an exact time, even an exact place because so many different things can happen. that's why this year we're using the tracker system, which people can follow on
diana nyad
.com to see where we are, how we're going, and where we might land and when.

>>i know the showstopper in the past has been these jellyfish stings, including the
box jellyfish
that releases toxins. that kind of knocked her out of it last tithe time. how is she handling the jellyfish this time around?

>>the first night we had a
rough night
. she had several jellyfish stings as did some of our shark team members who are in the water all the time. we have the foremost jellyfish expert with us this time around from the
university of hawaii
, who got to
diana
immediately and administered the proper care for those jellyfish stings. she did the
diana nyad
thing and powered through that night.

>>we just put a picture up of her wearing it looks like a mask and a full suit on that was supposed to protect her from jellyfish. has that been effective at all?

>>that's been super effective. that's something that
diana
has worked very hard on developing over the last year. unfortunately, you need every piece of skin of your body covered to have full protection against these things, and there's no way really to cover your lips. the stings she encountered the first night were on her lips.

>>mark, quickly before you go, i know she sings to keep her occupied. what is she singing these days? what does she like?

>>yesterday we had an awesome day. the weather was incredible. we got to see that classic
diana nyad
strokes. she came up and was actually singing
beatles songs
to the crew to lighten everybody up. it's an amazing thing to see.

>>i wonder if it was "
yellow submarine
." mark, good luck and tell her good luck.

The 62-year-old from Florida is on her fourth attempt to become the first person to swim from Cuba to Florida without a shark cage. Since leaving the Havana shore on Sunday morning, she has dealt with jellyfish stings on her neck, lips, hand and forehead as well as a nasty storm that rolled in Sunday night.

Mark Sollinger, the operations chief for Nyad’s 50-person support crew, checked in with Lester Holt live from the boat alongside Nyad on TODAY Monday.

“Things couldn’t look better right now,’’ Sollinger said. “The sun is up, and Diana is on what we call the streamer, which is what she follows. Her stroke looks good, and we’re moving in the right direction. A good stroke count for her is 50 (per minute), and she’s on that number right now.’’

If the 103-mile journey goes as planned, Nyad should reach the shore of Key West on Tuesday. Her ominous beginning included attacks from jellyfish, which rise to the surface at night and then retreat once the sun comes out in the morning. Nyad’s previous attempt at achieving the feat ended last September after about 40 hours and 90 miles of swimming following a series of box jellyfish stings.

“The first night we had a rough night,’’ Sollinger said. “She had several jellyfish stings, as did some of our shark team members who are in the water all the time. We have the foremost jellyfish expert with us this time around from the University of Hawaii, who got to Diana immediately and administered the proper care for those jellyfish stings. She did the Diana Nyad thing and just powered right through that night.’’

Nyad's special wetsuit, which covers everything but her face, has not completely insulated her from the stings.

“That’s been super effective,’’ Sollinger said. “Unfortunately, you need every piece of skin on your body covered to have full protection against these things. There’s no way really to cover your lips. The stings that she encountered the first night were on her lips.’’

A kayak-borne apparatus has been shadowing Nyad while generating a faint electric field to repel sharks. A team of shark handlers is also ready to dive in to distract sharks at a moment’s notice.

Nyad, who turns 63 on Wednesday, has maintained a positive mental attitude. Between periodic breaks to rest, hydrate and eat high-energy foods, she can often be found singing to keep the crew entertained.

“Yesterday we had an awesome day,’’ Sollinger said. “The weather was incredible, we all got to see that classic Diana Nyad stroke, and she came up for a couple of beats, and she was actually singing some Beatles songs to the crew to lighten everything up. It’s been amazing to see.’’

Nyad's first attempt at age 28, in 1978, ended after 41 hours when turbulent seas left her battered and delirious. Her second go, in August 2011, came to a halt following an 11-hour asthma attack and shoulder pain after 28 hours and 51 miles in the water.

She was 28 hours into the estimated 60-hour journey Monday morning. Her progress is regularly updated on her website, diananyad.com. Australian Susan Maroney is the only person to swim from Cuba to the United States, and she did it at 22 years old in May 1997 while using a shark cage. Exactly when Nyad could reach land on Tuesday is hard to ascertain, but she is determined to make history.

“There are so many variables involved in this with Mother Nature that it’s really tough for us to give you an exact time and even an exact place because so many different things can happen,’’ Sollinger told TODAY.

“I am not going to quit until I stand on the floor of the shore in Florida,’’ Nyad told NBC News before beginning her journey. “I’m going to make it across.’’

In a highly-anticipated speech to Congress Tuesday, Israeli Prime Minister Benjamin Netanyahu argued that a potential nuclear deal being negotiated by major powers including the United States "paves Iran's path to the bomb."